Credit

Caption

Asteroid approaching Earth, artwork. The Moon is in the background (upper left). Asteroids are rocky bodies orbiting within the solar system. They vary in size from tens of metres across to over a hundred kilometres across. A few asteroids have orbits that intersect with that of Earth. Large asteroids (over a kilometre across) impacting the Earth can cause mass loss of life. It is thought that this is what caused the extinction of the dinosaurs 65 million years ago.